Investigation on DPI effects in a low dropout voltage regulator

In this paper, the susceptibility of a low dropout voltage regulator (LDO) in direct RF power injection (DPI) is analyzed by measurements and simulation. The measurements highlight the offset in the output induced by the conducted RF disturbances and various failure modes. Discrete components used in the injection path and test board are modeled based on impedance measurements. DPI simulations using simple and complex models are presented, which highlight the strongly nonlinear behavior of the circuit even at low levels of power injection. The comparison between measurement and results of different models is given. And the reasons for the diversity of immunity level in frequency domain are analyzed.